Process for the treatment of metal surfaces and product thereof



Patented Mar. 4, 1947 PROCESS FOR THE TREATMENT OF METAL SURFACES ANDPRODUCT THEREOF Franklin B. Wells, Verona, N. J., assignor to Ellis-Foster Company, a corporation of New Jersey No Drawing. ApplicationDecember 1, 1942, Serial No. 467,556

2 Claims.

This invention relates to the protection of metal surfaces againstcorrosion. More particularly it relates to the temporary protection ofmetal surfaces, especially ferrous surfaces such as sheet steel, wire,etc., against corrosion and rusting due to moisture condensation duringshipment and storage.

As is well known, newly manufactured surfaces, especially ferroussurfaces, corrode rapidly unless treated with corrosion inhibitors. Inthe past many types of materials have been used for this purpose such asvarious grades of wool fat (lanolin), water-insoluble greases, mineraloils, petrolatums, asphalts, etc. These materials have all been foundsatisfactory as corrosion inhibitors within certain limits, the chiefobjection having been that, for the most part, relatively thick filmsare required to prevent corrosion and rusting. A thick film must beremoved before metal objects may be printed or lithographed, and in manycases, such as where mineral oil is used, inks or paints will not adhereproperly to the metal if oil is present. Thus, metal surfaces which havebeen treated with mineral oil, or thick films of other corrosion andrust inhibitors, must be pretreated in order to remove such protectivecoatings before painting, printing, or lithographing can be carried out.

This invention has as its object the provision of a method for treatingbright metal surfaces, especially ferrous surfaces, to inhibit corrosionand resting due to condensed moisture. Another object is to provide aprotective treatment for a metal surface, especially a ferrous surface,which wi11 adequately protect said surface against corrosion or rustingand which will not interfere with subsequent painting, printing, orlithographing on such surface.

These objects are accomplished by depositing on a ferrous metal surfacea thin continuous layer of a mixture of fatty acids, a mixture of higherfatty alcohols, and other unsaponifiable matter, or a mixture of fattyacidsand fatty alcohols and other unsaponifiablematerial. The mixturepreferably should form an homogeneous, substantially non-crystallinefilm under ordinary conditions of temperature.

Such a mixture comprises hydrolyzed lanolin obtained by the hydrolyticsplitting of the esters present in lanolin into a mixture of higherfatty acids and higher alcohols and other unsaponifiables. be separatedand used alone; or the crude mixture of acids and unsaponifiable mattermay be employed. Other materials may be added to the The acids and theunsaponifiablesmay hydrolyzed lanolin or the components thereof inamounts up to about 50% of the mixture. These include such substances astall oil and tallow or cottonseed oil fatty acids, etc. Also certainnitrogenous compounds such as alphanaphthylamine or phenylnaphthylaminemaybe advantageously included. The rustproofing materials are dissolvedin a suitable solvent and applied to the ferrous surface as a dilutesolution.

To form the corrosion-resisting material, lanolin is saponified by anyknown method. If the unsaponifiables are required the saponified productis extracted with a liquid which is a solvent for the unsaponifiables.When the lanolin fatty acids are required, the soap solution from whichthe non-soaps have been removed is acidified and the fatty acids takenup in a solvent. It is advantageous to use hydrolyzed lanolin whichcomprises the products obtained by saponifying lanolin and acidifyingthe mixture of soaps and alcohols to give a mixture of fatty acids andunsaponifiable material. The solvents used to take up thevarious lanolincomponents and to form the rustproofinig composition are preferablyvolatile coal-tar hydrocarbons, petroleum hydrocarbons containing aninfluential amount of aromatic hydrocarbons, or chlorinatedhydrocarbons. The solutions may be applied to articles having ferroussurfaces by dipping, spraying, flowing or brushing and the necessarythickness of film to produce rustproofing and a paintable surface issubstantially equal to that obtained by dipping the article in a 1 to10% solution of the substance in xylene, allowing excess solution todrain off and the residue to dry.

As metioned above, other substances such as tall oil may be added tohydrolyzed lanolin and its saponifiable and unsaponifiable components.Also, nitrogenous antioxidants may be introduced, this beingconveniently done by forming a waterinsoluble fatty acid salt thereof.For example, an amino compound such as a naphthylamine or bone oil isheated preferably with 'an excess of lanolin saponifiable matter or withacids such as tall oil or cottonseed oil acids and enough of thiscompound is used to introduce from about 11:0 10% of nitrogenousmaterial into the rustproofing composition.

A series of tests to illustrate the effectiveness of hydrolyzed lanolinproducts in comparison with other compositions was made wherein variousmaterials in 4% xylene solution were applied by dipping to strips of tincan base stock which had been abraded on a sanding machine. The stripswith their deposited films were suspended 3 over water in a closedcontainer and kept at about 40 C. for 96 hours. The following tableshows the degree of rust protection afforded by different materials, thedegree being a grading based on 100% for complete freedom from rust inthis time and being complete rusting of the surface. Untreated iron andtwo examples where the material was smeared on as a thick film are alsoincluded for comparison, as well as certain prior art materials.

. Degree of Number Composition protection Hydrclyzed lanolin 100 Lanolinfatty acids... 99 Lanolin unsaponifiablc 95 Tall oil. 90 50% talloil-50% hydrolyzed lanolin. 96 25% tall oil-75% hydrolyzed lanolin 98. 675% tall oil-25% hydrolyzed lanolin. 88 50% hydrolyzed lanolin-45% talloil- 99.5

5% alphanaphthylamine. 50% hydrolyzed lanolin-44% tall oil- 94. 5

6% phonyl-alphanaphthylamine. 90% tall oil10% alphanaphthylamine" 93 88%tall oil-12% phenylalphanaphthyl- 96 amine. Lanolin 10 Cottonseed fattyacid. 93 80% cottonseed fatty acid-20% alpha- 97 naphthylamine.Cholesterol 53 Coconut oil acids 94 Aluminum grease (smeared on) .1 100Lubricating oil (S.A.E. 50-Pcnna) 60 (smeared on). 19 Metal untreated 62Degree of protection Composition Water 5% NaOl Hydrolyzcd lanolin 96 92.5 Lanolin unsaponifiables 97 40 Lanolin fatty acids 96. 5 57 50%hydrolyzed lanolin-50% tall oil 90 50 50% hydrolyzed lanolin-45% talloil-5% alphanaphthylamine 92. 5 65 50% hydrolyzed lanolin-44% talloil-6% phenylnaphthylamine 94. 5 50 all oil 5 40 Coconut fatty acids 2.5 25 The concentration of lanolin fatty acids dissolved in xylene wasvaried as follows and the compositions applied to iron and tested as inthe first table:

Concentration Protection Per cent Per cent Also, a steel panel wascoated in sections with various concentrations of hydrolyzed lanolin inxylene. To portions of each section there were applied: (a) aconventional nitrocellulose lacquer, and (b) a commercial drying oilvarnish. The lacquer dried on all sections and also the varnish, exceptthat adhesion was better over films deposited from solutions containing10% or less of hydrolyzed lanolin. Therefore, the range of concentrationfor satisfactory rustproofing and paintability is from 1 to about 10%concentration.

It is known that: A film of lanolin thin enough to be painted over orprinted upon satisfactorily no longer possesses adequate corrosionresistance, and from commercial operations it has been apparent thatthere is no film thickness of lanolin which will prove satisfactory bothfor prevention of corrosion and for direct application of adherent paintcoatings or ink compositions. Therefore, it is entirely unexpected thatcompletely hydrolyzed lanolin or the separate ingradients thereof (acidsand unsaponifiable matter) show rust preventing properties in such anenhanced degree. It may be remarked that crude or rancid lanolin maycontain varying amounts of free fatty acid and may have been used forrustproofing. However, the hydrolyzed lanolin which I use has an acidcontent of entirely different magnitude. Also it may be noted that theunsaponifiable material from lanolin contains cholesterol in mixturewith other compounds and that a film of pure cholesterol shows poorrustproofing qualities whereas the crude cholesterol-containing materialis very effective,

I claim:

1. An article of manufacture having a ferrous surface and, in order torender said surface corrosion-resistant and at the same time capable ofbeing subsequently coated directly, a continuous thin film superposed onsaid ferrous surface and comprising completely hydrolyzed lanolin ob"-tained by hydrolyzing lanolin to a mixture of higher fatty acids andhigher alcohols, said film being of a thickness such as is obtained bydipping the article in a 1 to 10% solution of said material in xyleneand allowing same to drain and dry.

2. The process of rendering a ferrous surface corrosion-resistant and atthe same time capable of being subsequently coated directly, whichcomprises depositing on said surface a continuous thin film comprisingcompletely hydrolyzed lanolin obtained by hydrolyzing lanolin to amixture of higher fatty acids and higher alcohols, said film being of athickness such as is obtained by dipping an article having a ferroussurface in a 1 to 10% solution of said material in xylene and allowingsame to drain and dry.

FRANKLIN B. WELLS.

REFERENCE S CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,624,938 Fowler et a1 Apr. 19,1927 1,996,392 Torrence et al. Apr. 2, 1935 2,151,353 Montgomery Mar,21, 1939 2,153,811 Montgomery Apr. 11, 1939 FOREIGN PATENTS NumberCountry Date 163,474 British 1921

